Frequently, persons arrested and under transport in the rear seat of a patrol vehicle engage in violent actions, resulting in harm to themselves, extensive damage to the patrol car, and danger to officers and the public. The law enforcement community has suggested that vehicle safety air bags might be used to restrain individuals in these situations.
The objective of this system is to use an air bag to prevent an individual or individuals from continuing violent actions while being transported or detained in a patrol vehicle without requiring immediate physical contact by the law enforcement officer. The air bag independently restricts the amount of physical activity occurring in the rear seat of the vehicle while allowing the officer to safely stop the vehicle. The air bag can also provide the officer additional time to get backup personnel to aid him if the situation warrants it.
Front-seat vehicle safety air bags initiated the air bag restraint concept, but the actual hardware is of little use in meeting the design requirements that have been developed for the rear-seat patrol-vehicle air bag restraint system. Vehicle safety air bags certainly hold enough pressure, but they are designed for an entirely different purpose. Typically, safety air bags are a fabric material packaged inside the steering wheel or instrument patent. Deceleration sensors in the vehicle detect a frontal crash above a predetermined level of accident severity; then, a control module signals the inflation module to deploy the air bag. The inflator module includes a sealed canister containing sodium azide pellets. When the control module signals the inflator to deploy the air bag, the sodium azide undergoes a chemical reaction that rapidly generates nitrogen gas to inflate the bag. As the bag inflates, some residue will exist. This residue consists primarily of corn starch and/or talcum powder used by the manufacturer as a lubricant and byproducts of the chemical reaction. A small amount of sodium hydroxide dust, which is a potent irritant, is produced as a byproduct of the reaction, but the sodium hydroxide quickly converts to sodium carbonate and sodium bicarbonate. The bag inflates in approximately 0.05 seconds to full size, then deflates immediately through vent holes, helping to restrain the individual more gradually.
Under optimum conditions, individuals are handcuffed, placed in the vehicle, put in their seat belt, and then transported to their designated deterrent location, usually a police station. This scenario adequately defines the geometric configurations an individual can be in; however, these optimum conditions do not always occur. Since no single geometric configuration defines how a person sits in the vehicle, the air bag must be designed to handle all possible configurations. There is no standard profile of what type of person (e.g., large person, male, young, etc.) is most often involved in violent outbursts so no body type determinations could be made. The type of violence that occurs is also quite varied. Usually, individuals use their legs to break windows, push on the front seat or the barrier, or damage doors. Instances have occurred where officers have been injured by individuals using items such as belt buckles to cut them, as well as cases where individuals have broken out the rear window, crawled out, and then been killed by an oncoming vehicle. The conclusion drawn from discussions with law enforcement personnel is that there is no typical violent individual, no typical condition under which violence occurs, and no typical type of violent action.
The use of the air bag allows an officer the optimum ability to protect the public, to protect a suspect from personal injury, and to allow enough time to remove the patrol vehicle from traffic and regain control. Also, the use of the air bag protects the officer from sustaining injury at the hands of a suspect who desires to break free or cause bodily harm.